857 



than Pb, a part from ^.1. The curve remains, therefore, within the 

 triangle as well on increase as on decrease of P. 



c) Both the binary I\ 7-curves proceed from the point B towards 

 higher pressures; consequently two points of maximumpressure occur 

 [ TFx <^ 0, A fI",/<^0; case sub c; fig. 4 — 6]. A boilingpointcurve 

 situated in the vicinity of B cuts off from the side JiC a smaller 

 part than from the side BA. The (;urve comes, on increase of P, 

 within the triangle. 



In each of the cases, mentioned sub a, b, c, the temperature along 

 a boilingpointcurve situated in the vicinity of B, increases in that 

 direction in which this curve comes nearer to B (tigs. 3 — 6). 



(76» be continued). 



Chemistry. — -'Studies in the Field of Silicn/.e-C/ieinistn/ : 1. On 

 Compounds of Lithiumo.vide and Silica. By Pi-of. Dr. F. M. 

 Jaeger and Dr. H. S. van Klooster. (Communicated by Prof. 



P. VAN ROMBURGH.) 



§ 1. In connection with a series of investigations going on in 

 this laboratory, on natural and synthetical lithiumaiuminiumsilicates, 

 it seemed to us of importance once more to take up the study of 

 the binary systeiTi : lithiumoxide-silica, by means of the equipment 

 and methods, which are now at our disposal ; only in this way it 

 seemed to us possible, to obtain thermical data, which are reliable 

 and reducible to the nitrogen gasthermometer. At the same time 

 we hoped to get information on the origin of in some resi)ects rather 

 strongly deviating results of earlier investigators, who have occupied 

 themselves also with the study of these lithiumsilicates. 



The two-componentsystem : LijO — SiOj has alread}' sevei-al times 

 been an object of research ; thus some time ago by one of us '), 

 using the method, already so often successfully employed upon metal- 

 alloys, of the crystallization phenomena on cooling, which will show 

 themselves in such binary mi.xtures of varying composition. Later it 

 was studied in the same way by Endell and Rieke '), who of course in 

 general also came to the same results, but who were not able finally to 

 answer the question, if a third compound, the lithiuml)isilicate, could 

 separate from molten mixtures, like the oitho-, oi- meta-silicate. 



1) H. S. VAN Klooster, Dissertatie Grüniiigen (1910); Zeits. f. anorg. Choinio 

 69, 136 (1910). 



-) K Endell und R. Rieke, Spreclisaal, 44. Nu 46 (1910); 45. No 6 (1911). 



55* 



